Zinc–air batteries in neutral/near-neutral electrolytes

To fully utilize intermittent renewable energy and have energy security, large-scale batteries are necessary. The aqueous zinc–air battery (ZAB) is a promising potential candidate for its safety, low-cost, and theoretical capacity. This research on ZAB mainly focused on alkaline electrolytes. These are favored for their conductivity, but greatly reduce the stability of the battery by zinc corrosion from the hydrogen evolution reaction (HER), dendrite formation, and carbonate formation. To address these issues, recently neutral and near-neutral electrolytes have been applied to aqueous ZAB to suppress HER, dendrite formation, and minimize carbonate formation. These include the use of chloride-based, potassium nitrate, aqueous organic, solid-state electrolytes supplemented with additives to improve the performance and stability. This field is still young with significant opportunities available for research.

A Sight of Zinc Corrosion in Various Alkaline Media

This review concentrates on corrosion properties that expose to zinc by various alkaline media. The assumption has been advanced that zinc corrodes electrochemically in the first stage of exposition, but the chemical corrosion prevails after a longer time. Different types of electrolyte had been tested on zinc such as sodium chloride, sodium hydroxide and potassium hydroxide. Each of alkaline media can produced corrosion product such as zinc hydroxide chloride, zinc hydroxide carbonate, zinc oxide, and zinc hydroxide. The production of corrosion products is depending on the carbon dioxide content that introduced to the air. Potassium hydroxide is the highest and active alkaline where it contains the highest ionic conductivity potassium ions, K+ after hydronium, H3O+ among the cations and hydroxide, OH ? has the highest ionic conductivity among the anions.